Neighbour noise

I really need help to assist my friend who I care for and have a flat below him. A guy has moved in (its a block of 6 flats) who keeps slamming doors sometimes at 2 or 3am. I tried asking him to stop but he dinied it was him. I then tried putting a note under his door eplaining how it effects my friend but still it continues, I have notified our landlords who wish to evict him but that will take some time. I need to know how to help my mate as he is constantly worrying about the noise and talking about it all the time. I cannot get him motivated to do anything. Ive suggested walks in the park, vistis to musems,the library and other things he is interested in. Any advice be much appreciated. Thank you